I've lived in Australia for years and one question that's always bugged me is why didn't the Polynesians ever colonise Australia, or at the very least why didn't some polynesians reach Australia (and thereby affect the behaviour of the indigenous peoples of the south-eastern/eastern coast at the least)? I can understand that there may have been a preference for traditional ways of doing things perhaps, but the technology of the polynesians should have given them an advantage, and their maritime skills should have enabled them to reach Australia I would have thought.
Pacific wind patterns almost certainly also played a role. Polynesian expansion was usually against the prevailing winds. That's because, if you sail into the unknown, and start to run out of food and water, you're more likely to make it back. This seems to be why New Zealand was settled so late, and also why the main migration push never curved back to Australia. See, http://www.teara.govt.nz/en/diagram/1777/upwind-survival-strategy
From a previous thread:
Just north of Australia is Torres Strait (it's the yellow spot in this picture), which separates Cape York, the northernmost point of Australia, from Papua New Guinea. The Torres Strait Islands, with Papua New Guinea, and the surrounding islands make up the biogeographical region known as Melanesia.
The Melanesians are recognised as a separate genetic group to the Polynesians (warning: PDF link), with it being theorised that the Polynesians passed through Melanesia:
the researchers state that their analysis is consistent with the scenario that the ancestors of Polynesians moved through Island Melanesia relatively rapidly and only intermixed to a very modest degree with the indigenous populations there.
In short, it looks like the Polynesians didn't come to Australia because the Melanesian islands immediately to the north of Australia were already occupied, so they had to keep going to find unoccupied islands further out in the Pacific.
Here's a map that will help you see the migration routes and dates.
Credit to /u/Algernon_Asimov. Link
To kind of piggyback with a similar question, how was it that people made it clear out to Hawaii but no one managed to colonize the Americas by boat until much much later?
